Actuatable occupant restraint systems are used to help protect occupants of a vehicle in the event of a vehicle crash event. Such an actuatable occupant restraint systems may include an inflatable occupant restraint device, such as an air bag, to help protect a vehicle occupant upon the determined occurrence of a vehicle collision or a vehicle rollover event.
U.S. Pat. No. 5,935,182 to Foo et al., assigned to TRW Inc., discloses a method and apparatus for determining such crash events and is particularly directed to discriminating a vehicle crash condition using virtual crash sensing. U.S. Pat. No. 6,600,414 to Foo et al., also assigned to TRW Inc., discloses a method and apparatus for determining a vehicle rollover event that includes a discriminating safing function. U.S. Pat. Nos. 5,890,084 and 6,600,985 and U.S. Patent Application Publication 2006/0235575 all disclose the detection of vehicle rollover events, including detection of roll rate and/or angular rate about a vehicle's Y-axis.